Dispensers for flexible sheet material such as paper toweling have long been known. They find their widest application in public lavatories where they hang on walls to dispense paper toweling for users to dry their hands. The dispensers usually have a crank, a lever or a metered crank mechanism which the user operates to dispense toweling. The crank and lever mechanisms are continuously operable so that the user can withdraw any length of towel, whereas the metered crank mechanism allows the user to withdraw only a predetermined length of towel so as to thereby conserve paper.
The following patents are representative of the prior art:
______________________________________ U.S. Pat. No. Issue Date Original Assignee ______________________________________ 3,382,021 5/07/68 Continental Mfg. Co. 3,606,125 9/20/71 Towlsaver, Inc. 3,613,880 10/19/71 Towlsaver, Inc. RE 28,911 Reissued Georgia-Pacific Corp. 7/20/76 4,106,684 8/15/78 Crown Zellerbach Corp. 4,165,138 8/21/79 Mosinee Paper Co. 4,260,117 4/07/81 Towlsaver, Inc. ______________________________________
Prior art dispensers generally comprise a back or body, paper feed rollers, a dispensing mechanism operable by the user to drive the feed rollers, and a door or cover. The preferred material for the various components in most of the prior art dispensers was sheet metal, with the exception that the feed rollers were usually made of wood.
Prior art dispensers usually required many different parts and were attended by complex secondary operations to assemble a dispenser. For example, a body for a dispenser may have required a cutting element with which to sever a dispensed length of paper toweling, hinge elements to connect a door to the body, and a lock to lock the door shut against the body to inhibit unauthorized opening. Each of these parts was mechanically fastened to the body, such as by riveting. This required at least three different subassembly stations on at least three different machines using relatively complicated tooling which was quite susceptible to breakdown. Of course, the maintenance and replacement of tooling required for these secondary operations was expensive, but, even more importantly, the time it took to perform the operations was expensive.
The prior art constructions also aggravated inventory control and production planning problems. In production, each individual part of an assembly and each subassembly operation must be accounted for to insure that the requisite parts and subassemblies are available to meet production demands. Accordingly, the difficulty of inventory and production planning is directly proportional to the number of parts and secondary operations required to produce a finished product. Moreover, in the prior art, the susceptibility of the secondary operation machines to breakdown continuously threatened the production planner with preventing him or her from meeting the production schedule.
Also, the structure of prior art dispensers did not provide for facile conversion of a dispenser's mode of operation, for example, from a crank mode to a lever mode. While the prior art encompasses dispensers having various parts of their dispensing mechanisms together in a single subassembly, the prior art does not disclose a flexible design system in which a dispenser mechanism module is an interchangeable part of the dispenser cabinet wall structure to provide facile conversion of the dispenser's mode of operation by simply changing the module. Interchangability of a mechanism module unit is desirable because it provides for ease of assembly, simplifies production planning as the various modules can be subassembled and subsequently combined with the other common dispenser components to produce a dispenser of the desired mode, and provides for relative ease of service in the field.